Field of the Invention
Embodiments of the present invention relate to a light-guide member, an illumination device, and an image reading apparatus, and more particularly to an image reading apparatus, such as an image scanner, a copying machine, or a facsimile machine, that performs image reading by illuminating a surface of a document by a line-sequential method.
Description of the Related Art
An image reading apparatus that obtains information regarding an image of a document includes an illumination device that illuminates a to-be-read region of a document. A known example of an illumination device is an illumination device that includes a light-guide member that guides light emitted by a light source to a surface to be illuminated.
There is known an illumination device that includes a reflective plate, which is disposed at a position facing a light-guide member with a reading optical axis interposed therebetween, and that illuminates a region to be illuminated from two directions by using only one light-guide member, the two directions being symmetrical about the reading optical axis. More specifically, Japanese Patent Laid-Open No. 2011-044336 discloses a light-guide member that is included in an illumination device, which illuminates a region to be illuminated from two directions, the two directions being symmetrical about the reading optical axis, and that has a deflecting portion that deflects light to a position facing a light-emitting surface.
However, in the above-described related art, deflecting portions are provided so as to correspond to first and second light-emitting regions, respectively, and high processing precision is required for each of the deflecting portions in order to realize a highly efficient light-guide member. Thus, there has been a problem in that the configuration of metal molds used for molding the light-guide member becomes complex.